


Pent Up

by SinningfortheWinning



Category: Gravity Falls
Genre: Cheerleaders, Dead Dove: Do Not Eat, F/M, Forced Orgasm, Forced Pregnancy, Gags, Light Bondage, Rape/Non-con Elements, Somnophilia, Underage Sex
Language: English
Status: Completed
Published: 2020-08-18
Updated: 2020-08-18
Packaged: 2021-03-06 11:26:50
Rating: Explicit
Warnings: Rape/Non-Con, Underage
Chapters: 1
Words: 1,409
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25968856
Author URL: https://archiveofourown.org/users/SinningfortheWinning/pseuds/SinningfortheWinning
Summary: Dipper is a horny teenager and his sister is hot easy prey.
Relationships: Dipper Pines/Mabel Pines
Comments: 1
Kudos: 87





	Pent Up

**Author's Note:**

> There's a lot of you that seem to like these stories so here's another one. I take kink requests. Can't promise I'll get to them all but I'll try.

Dipper knows he shouldn't be in the girls locker room. He knows that hiding there and waiting for his twin is wrong too and yet he remains in the supply closet with his rope and gag ready.

Mabel has been a tease their entire life and now that they're in junior high his hormones are raging over it. Puberty has hit them both and their parents got them separate rooms. A huge mistake if they wanted their 14 year olds to be virgins for much longer.

He used to be able to get his need to cum out by jerking off and sticking the head of his cock into his sleeping sister's mouth to make it so there's no mess. But now sneaking into a whole other room makes too much noise with their creaky floorboards.

The one time he tried to hint at wanting to fuck Mabel told him he was gross and thought Dipper was joking. Him ramming his cock into her in the dark closet while she can't move or scream will be no joke though.

Dipper is about to whip out his cock and jerk off to the idea when the door to the locker room finally opens. He had hid her phone and caused her to forget it, making her run ahead of the others to get it before they changed out of their cheerleading gear.

He doesn't give her the chance to change. Dipper thinks the slutty outfit is hot and the skirt just means easy access.

When he pops out of the closet he makes sure to come up behind her so she doesn't see her attacker. The gag is shoved in her mouth first then he uses the rope to yank her back into the closest by the throat. In the dark he's able to tie her hands behind her back despite her surprised struggles.

Knowing his twin, she probably thinks this is just some fun prank so she's not fighting very hard. Dipper is glad for it as he bends her over on a shelf and holds her down with one hand.

His other hand is freeing his cock, a decently sized one if he did say so himself.

Mabel's struggling becomes a little more frantic when Dipper places his hand on her pussy over the thin underwear she has under the skirt. His fingers awkwardly begin to explore her folds to try and get her wet enough for him to get his dick in.

His twin stats to cry around the gag when her cunt dribbles out enough precum to soak through the panties. They're easily moved to the side, exposing her perfect little pussy.

Dipper's heard about "eating pussy" before and knows he needs to try it. When in Rome, after all. He kneels down and Mabel stays where she is for him out of fear. It doesn't smell like he expected it to but his body responds to the wet scent so he decides he likes it.

Not knowing how else to do it, Dipper mashes his mouth against his twin's cunt and begins to make out with it. Mabel squeals around the gag and her hips jerk towards his face so Dipper pushes his mouth against her more.

It tastes odd, almost bitter but not bad. All the porn in the world never explained the eating part though and Dipper figures it's hard to get a good shot of using teeth on such an area. He opens wide and uses his bottom teeth to rub her clit.

He might be doing it too hard because Mabel is trying to scream when he starts. Or maybe that means she likes it. Either way, Dipper continues to eat her pussy aggressively because his cock is throbbing eagerly to be forced inside of her and her wants her nice and wet for it.

When her legs quiver and shake he feels a warm gush of liquid spill from her opening. His first time eating a girl out and he made her cum. That's enough to send him to his feet smiling, getting his hard cock lined up with the soaking pussy.

His twin is trying to struggle and he's sure it's because she's not on birth control and knows if someone came in her she'll get pregnant. Dipper has no plans of pulling out.

Dipper is excited and breathing heavily with sweat forming on his forehead as he grips his sister's hips as tight as he can. She's wet but the head of his cock is meeting a lot of resistance. He has to wiggle his hips before he feels himself slip into her.

Her pussy has only managed to swallow the head but what a feeling it is. Hot wet and so very tight. Dipper has to breathe a few times so that he doesn't bust in her too soon. She's sobbing, muffled by the gag, and he knows he's popped her cherry.

If his voice wouldn't give him away Dipper would let her know how good she feels. He tells her silently by ramming the rest of his dick into her. It's about nine inches so he knows it's big for their age. Which is why Mabel spasms when the base of it is right at her opening and the head is hitting some sort of wall of warm flesh.

Dipper can't keep his hips from moving and starts to fuck his twin with the eagerness of a dog in heat. His thrusts are making the shelf shake and Mabel's large breasts are wiggling their way out of the deep V neckline of her cheerleading top.

Dipper reaches up and grabs the shirt to rip them free. There's a bra still in the way but his hand can easily slide under it to grope his sister's perfect tit. They always looked so soft and he's happy to feel that they are.

Through the door he can hear the other girls coming into the locker room. They're chatting loudly while Mabel cries from how hard Dipper is pinching her nipple.

"Where's Mabel?" one girl asks.

"She probably went home or to the bathroom. I bet she's with that weird brother of hers. I swear to god he's always looking at my boobs."

Dipper knows that's Jessy talking. If he could he'd trap her in there too. She would be more difficult though.

Mabel's legs shake again and Dipper isn't prepared for the way her pussy squeezes him. He's no doubt making some stupid face but he's in ecstasy. His dick that's only ever known his hand is now balls deep in a hot babe who's coming because he fucked her.

It's a confidence boost that makes him ram into her harder. He's so close and quietly grunting while using both hands to grab Mabel's boobs, her back firmly against his chest. It sounds like his thrusts are hurting her every time he shoves it in all the way but he's too close to care.

His orgasm finally comes and he slams into his twin to the sound of the other girls laughing and talking about their day. He can feel the stream of cum gush into his sister, no doubt getting her knocked up.

When the last of it dribbles out Dipper pulls out and let's his twin fall to the floor. She's crying and he can't really find it in himself to care when it had felt so good.

Dipper waits until the girls leave then leaves as well like nothing happened. He goes to his locker then walks home, saying he thought Mabel was with her girl friends while his twin is left with her tits out and her pussy leaking his cum for the janitor to find an hour later.

The police are called but Mabel refuses to talk about it. For the next week she doesn't go to school and hardly speaks to anyone.

When she finally does speak a lot it's to their parents. She asks to share a room with Dipper again because it'll make her feel safer and they all agree.

His twin is no doubt thinking that he'll be a layer of protection but the very first night they share together he's slipping his cock into her mouth and throat like he used to because his twin sleeps like a rock.

If his parents hadn't wanted to be grandparents so early, they should have never taken this away from him.

**Author's Note:**

> Maybe I'll write more of Mabel getting back at Dipper soon. And I don't edit this crap so if there's a mistake either deal with it or tell me and I'll fix it.


End file.
